Maritime economics: Problems and challenges for the future

The light is always identical in its composition, but it falls on a great variety of objects, and by so falling is first revealed to us, not in its own form, for it is formless, but in theirs; in like manner, thought only appears in the objects it classifies.     

On the definition of traffic equilibrium

Three alternative definitions of traffic equilibrium are compared in terms of the mechanisms of route-choice inherent in them. These definitions are the usual Wardrop equilibrium and user-optimised ones and a new one. Conditions on the cost function are established under which the Wardrop definition is equivalent to each of the other two. Some circumstances are identified in which these conditions are satisfied. A detailed discussion is given of an example in which these conditions are not satisfied and the three definitions are not equivalent.     

Systematic training for maritime transport managers

Providing effective training for managers in the maritime and ports sector in developing countries has proven to be a daunting task. Initial attempts by the United Nations Conference on Trade and Development (UNCTAD) in the 1970s led to the development of senior port manager residence courses in Sweden. However, Given the vast numbers of managers needing training a more eficient method was required. Using the systematic training techniques pioneered by the International Telecommunications Union, UNCTAD, in the 1980s initiated two parallel programme: Trainmer (Training development in Maritime Transport); and IPP (Improving Port Performance). Both of these programmes demonstrated considerable success in terms of the numbers of maritime and port managers receiving training opportunities. Increased cooperation amoungst international agencies providing training programmes should result in improved transport management training in the 1990s, lrading to increased efficiences in port and related transport systems.     

Gulf of Gdansk spring bloom physical, bio-optical, biological modelling and contact data assimilation

In this study we propose a model of phytoplankton population dynamics in the marine ecosystem, which includes physical, biological and bio-optical parts. As an example we simulate the abnormal 1993 Gulf of Gdansk spring bloom, when extremely high chlorophyll concentrations were observed. For the one-dimensional model we use two different methods of contact chlorophyll observation assimilation to fit a model of “in situ” data. The results are compared with two-dimensional ecosystem modelling based on a barotropic model of wind-driven circulation without assimilation.     

Fuzzy and adaptive fuzzy control for the automobiles' active suspension system

Two typical criteria for good vehicle suspension performance are their ability to provide good road handling and increased passenger comfort. The main disturbance affecting these two criteria is terrain irregularities. Active suspension control systems reduce these undesirable effects by isolating car body motion from vibrations at the wheels. This paper describes fuzzy and adaptive fuzzy control (AFC) schemes for the automobile active suspension system (ASS). The design objective is to provide smooth vertical motion so as to achieve the road holding and riding comfort over a wide range of road profiles. The efficacy of the proposed control schemes is demonstrated via simulations. With respect to the optimal linear quadratic regulator (LQR), it is shown that superior results have been achieved by the AFC.     

Hatchcoverless container ships: productivity gains from a new technology

The hatchcoveless container ship is an innovative design which improves cargo handling productivity. The paper develops a methodology for measuring the gains. To illustrate the impact of faster port times on voyage profitability a voyage cost analysis is used to show its operational advantages. An investment analysis demonstrates the value which will accrue to the company over the life of the vessel.     

A study of the changes in performance of quayside container cranes

The learning effect, whereby performance improves with experience, is well documented for manufacturing situations. This article applies these learning concepts to quayside container cranes, in order to determine the relationship between number of containers moved and unloading time. The results show that crane performance has improved with time, and that the learning effect is essentially the same for four ports. Container vessel operators are looking for consistency in port operations. An analysis of variability for one port shows that this consistency is not always achieved and that crane performance does not appear to be related to vessel size.     

Energy savings due to land transportation management in Singapore

Singapore has been actively engaged in implementing various land transportation policies and traffic management schemes since the early 1970s to reduce traffic congestion. This paper examines the benefits in energy savings arising from the following five major schemes: (a) the Area Licensing Scheme, (b) the computerised Area Traffic control System, (c) the adaptive traffic control system, (d) the exclusive bus lane scheme, and (e) the island-wide expressway system. The analyses are made based on the findings of a two-year study that developed vehicle fuel consumption models for Singapore traffic. The Area Licensing Scheme that restricts traffic flow into the Central Business District (CBD) is found to have the greatest energy impact, followed by the island-wide expressway system and the traffic-signals control systems within the CBD.